Configuring transmission resources during storage area network migration

1. A method comprising: determining, by one or more processors, throughput of hardware devices operatively coupled to a target Storage Area Network (SAN) prior to a SAN migration from a source SAN to the target SAN; retrieving, by one or more processors, a soft state from a source SAN processor utilized by the source SAN, wherein the source SAN processor includes a processor core, wherein the soft state is stored in buffers within the processor core, and wherein each buffer within the processor core contains an intermediate execution output of a component within the processor core; retrieving, by one or more processors, information from a Network Interface Card (NIC) queue in the source SAN and a Local Area Network (LAN) queue in the source SAN, wherein the NIC queue in the source SAN contains queued data to send to the target SAN, and wherein the LAN queue in the source SAN includes configuration packets used in the SAN migration; determining, by one or more processors, an estimated time duration required to retrieve the soft state from a central processing unit (CPU) queue in the source SAN processor and the information from the NIC queue and the LAN queue in the source SAN, and to migrate the soft state of the processor core and the information from the NIC queue and the LAN queue in the source SAN from the source SAN to the target SAN; determining, by one or more processors, an estimated size and time of the SAN migration from the source SAN to the target SAN based on the estimated time duration required to retrieve the soft state from the CPU queue in the source SAN processor and the information from the NIC queue and the LAN queue in the source SAN, an estimated time to migrate the soft state of the processor core and the information from the NIC queue and the LAN queue in the source SAN from the source SAN to the target SAN, and the throughput of the hardware devices; and configuring, by one or more processors, transmission resources available to the source SAN to comport with the estimated size and time of the SAN migration from the source SAN to the target SAN.

2. The method of claim 1 , further comprising: further determining, by one or more processors, the estimated size and time of the SAN migration by using a SAN virtualized switch, wherein the SAN virtualized switch simulates the throughput of the hardware devices operatively coupled to the target SAN by emulating switch ports used by the target SAN.

3. The method of claim 2 , further comprising: determining, by one or more processors, Input/output Operations Per Second (IOPS) of the hardware devices; and determining, by one or more processors, the IOPS and throughput of the hardware devices operatively coupled to the target SAN based on an M/M/ 1 queue of the SAN virtualized switch, wherein the M/M/ 1 queue represents a queue length of a queue for the SAN virtualized switch based on an arrival rate of packets at the SAN virtualized switch and a departure rate of packets from the SAN virtualized switch.

4. The method of claim 3 , further comprising: determining, by one or more processors, the arrival rate and the departure rate by a Poisson process that predicts the arrival rate and the departure rate at different predicted time points during the SAN migration.

5. The method of claim 3 , further comprising: predicting, by one or more processors, a root cause of a throughput slowdown during the SAN migration based on the IOPS and the throughput of the hardware devices.

6. The method of claim 1 , further comprising: determining, by one or more processors, the throughput of hardware devices operatively coupled to the target SAN according to a production throughput, wherein the production throughput is equal to total available bandwidth for SAN migration minus bandwidth used by currently running production workloads on the target SAN.

7. A computer program product for configuring transmission resources available to a source Storage Area Network (SAN) to comport with an estimated size and time of a SAN migration from the source SAN to a target SAN, wherein the computer program product comprises a non-transitory computer readable storage device having program instructions embodied therewith, the program instructions readable and executable by a computer to perform a method comprising: determining throughput of hardware devices operatively coupled to a target Storage Area Network (SAN) prior to a SAN migration from a source SAN to the target SAN; retrieving a soft state from a source SAN processor utilized by the source SAN, wherein the source SAN processor includes a processor core, wherein the soft state is stored in buffers within the processor core, and wherein each buffer within the processor core contains an intermediate execution output of a component within the processor core; retrieving information from a Network Interface Card (NIC) queue in the source SAN and a Local Area Network (LAN) queue in the source SAN, wherein the NIC queue in the source SAN contains queued data to send to the target SAN, and wherein the LAN queue in the source SAN includes configuration packets used in the SAN migration; determining an estimated time duration required to retrieve the soft state from a central processing unit (CPU) queue in the source SAN processor and the information from the NIC queue and the LAN queue in the source SAN, and to migrate the soft state of the processor core and the information from the NIC queue and the LAN queue in the source SAN from the source SAN to the target SAN; determining an estimated size and time of the SAN migration from the source SAN to the target SAN based on the estimated time duration required to retrieve the soft state from the CPU queue in the source SAN processor and the information from the NIC queue and the LAN queue in the source SAN, an estimated time to migrate the soft state of the processor core and the information from the NIC queue and the LAN queue in the source SAN from the source SAN to the target SAN, and the throughput of the hardware devices; and configuring transmission resources available to the source SAN to comport with the estimated size and time of the SAN migration from the source SAN to the target SAN.

8. The computer program product of claim 7 , wherein the method further comprises: further determining the estimated size and time of the SAN migration by using a SAN virtualized switch, wherein the SAN virtualized switch simulates the throughput of the hardware devices operatively coupled to the target SAN by emulating switch ports used by the target SAN.

9. The computer program product of claim 8 , wherein the method further comprises: determining Input/output Operations Per Second (IOPS) of the hardware devices; and determining the IOPS and throughput of the hardware devices operatively coupled to the target SAN based on an M/M/ 1 queue of the SAN virtualized switch, wherein the M/M/ 1 queue represents a queue length of a queue for the SAN virtualized switch based on an arrival rate of packets at the SAN virtualized switch and a departure rate of packets from the SAN virtualized switch.

10. The computer program product of claim 9 , wherein the method further comprises: determining the arrival rate and the departure rate by a Poisson process that predicts the arrival rate and the departure rate at different predicted time points during the SAN migration.

11. The computer program product of claim 9 , wherein the method further comprises: predicting a root cause of a throughput slowdown during the SAN migration based on the IOPS and the throughput of the hardware devices.

12. The computer program product of claim 7 , wherein the method further comprises: determining the throughput of hardware devices operatively coupled to the target SAN according to a production throughput, wherein the production throughput is equal to total available bandwidth for SAN migration minus bandwidth used by currently running production workloads on the target SAN.

13. A computer system comprising: one or more processors; one or more computer readable memories; one or more computer readable storage mediums; and program instructions stored on at least one of the one or more computer readable storage mediums for execution by at least one of the one or more processors via at least one of the one or more computer readable memories to perform a method comprising: determining throughput of hardware devices operatively coupled to a target Storage Area Network (SAN) prior to a SAN migration from a source SAN to the target SAN; retrieving a soft state from a source SAN processor utilized by the source SAN, wherein the source SAN processor includes a processor core, wherein the soft state is stored in buffers within the processor core, and wherein each buffer within the processor core contains an intermediate execution output of a component within the processor core; retrieving information from a Network Interface Card (NIC) queue in the source SAN and a Local Area Network (LAN) queue in the source SAN, wherein the NIC queue in the source SAN contains queued data to send to the target SAN, and wherein the LAN queue in the source SAN includes configuration packets used in the SAN migration; determining an estimated time duration required to retrieve the soft state from a central processing unit (CPU) queue in the source SAN processor and the information from the NIC queue and the LAN queue in the source SAN, and to migrate the soft state of the processor core and the information from the NIC queue and the LAN queue in the source SAN from the source SAN to the target SAN; determining an estimated size and time of the SAN migration from the source SAN to the target SAN based on the estimated time duration required to retrieve the soft state from the CPU queue in the source SAN processor and the information from the NIC queue and the LAN queue in the source SAN, an estimated time to migrate the soft state of the processor core and the information from the NIC queue and the LAN queue in the source SAN from the source SAN to the target SAN, and the throughput of the hardware devices; and configuring transmission resources available to the source SAN to comport with the estimated size and time of the SAN migration from the source SAN to the target SAN.

14. The computer system of claim 13 , wherein the method further comprises: further determining the estimated size and time of the SAN migration by using a SAN virtualized switch, wherein the SAN virtualized switch simulates the throughput of the hardware devices operatively coupled to the target SAN by emulating switch ports used by the target SAN.

15. The computer system of claim 14 , wherein the method further comprises: determining Input/output Operations Per Second (IOPS) of the hardware devices; and determining the IOPS and throughput of the hardware devices operatively coupled to the target SAN based on an M/M/ 1 queue of the SAN virtualized switch, wherein the M/M/ 1 queue represents a queue length of a queue for the SAN virtualized switch based on an arrival rate of packets at the SAN virtualized switch and a departure rate of packets from the SAN virtualized switch.

16. The computer system of claim 15 , wherein the method further comprises: determining the arrival rate and the departure rate by a Poisson process that predicts the arrival rate and the departure rate at different predicted time points during the SAN migration.

17. The computer system of claim 15 , wherein the method further comprises: predicting a root cause of a throughput slowdown during the SAN migration based on the IOPS and the throughput of the hardware devices.